-- if
a = 10

if(a < 20) then 
    print("a < 20")
end
--> a < 20

-- if else

a = 30

if(a < 20) then
    print("a < 20")
else
    print("a > 20")
end
--> a > 20

-- if elseif
if(a < 20) then
    print("a < 20")
elseif(a < 40) then 
    print("20<= a < 40")
else
    print("other")
end
--> 20<= a < 40



